Post-transplant distal limb syndrome: clinical diagnosis and long-term outcome in 37 renal transplant recipients

After the introduction of steroid sparing immunosuppressive protocols, osteonecrosis of the hip has become a rare entity in renal transplantation. Instead, an elusive bilateral pain syndrome of the distal extremities has gained more clinical attention. Because of the typical presentation, it is sometimes referred to as 'post-transplant distal limb syndrome' (PTDLS). The syndrome typically manifests during the first year after transplantation and may lead to significant morbidity because of pain induced immobilization. On MRI-scans, a characteristic bilateral patchy osteoedema can be demonstrated. The etiology of PTDLS has not been determined definitely so far. Over the last 8 years, we have seen the syndrome in 37 out of 639 renal transplant patients (5.8%). There was no association to steroid-medication, age, gender, PTH levels or delayed graft function. As an important finding, we saw a significant rise in alkaline phosphatase from 160 +/- 54 to 271 +/- 108 U/l (P = 0.001) and calcium from 2.46 +/- 0.18 to 2.58 +/- 0.18 mmol/l (P = 0.013) preceding the onset of pain by several weeks. Mean duration of clinical symptoms was 5.1 +/- 3.1 months; however, all patients experienced remission without signs of chronic damage on long-term follow up.